It's one of many environmentally friendly moves cities and states have been making lately. Single-use plastic bags are now banned in many places, while a number of restaurants have stopped offering straws altogether or are only using paper straws instead.

Restaurants in Maine will now have to find alternatives to Styrofoam to-go packaging. The state's governor, Janet Mills, says she's proud Maine is leading the way.

"Polystyrene cannot be recycled like a lot of other products, so while that cup of coffee may be finished, the Styrofoam cup it was in is not," Mills said in a written statement obtained by CNN. "In fact, it will be around for decades to come and eventually it will break down into particles, polluting our environment, hurting our wildlife, and even detrimentally impacting our economy."